<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta http-equiv="X-UA-Compatible" content="ie=edge">
  <script src="https://cdn.staticfile.org/react/16.4.0/umd/react.development.js"></script>
  <script src="https://cdn.staticfile.org/react-dom/16.4.0/umd/react-dom.development.js"></script>
  <script src="https://cdn.staticfile.org/babel-standalone/6.26.0/babel.min.js"></script>
  <title>Document</title>
</head>
<style>
  .box {
    width: 50px;
    height: 50px;
    background-color: seagreen;
  }
</style>

<body>
  <div id="demo">

  </div>
  <script type="text/babel">

    var myElement = <div className="box" />
    ReactDOM.render(
      myElement,
      document.getElementById('dome')
    )




  </script>
</body>

</html>